cfq-iosched: fix think time allowed for seekers
Corrado Zoccolo [Wed, 7 Oct 2009 17:51:54 +0000 (19:51 +0200)]
CFQ enables idle only for processes that think less than the allowed
idle time. Since idle time is lower for seeky queues, we should use the
correct value in the comparison.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

block/cfq-iosched.c

index 4ab33d8..b35cc56 100644 (file)
@@ -1995,7 +1995,10 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
            (!cfqd->cfq_latency && cfqd->hw_tag && CIC_SEEKY(cic)))
                enable_idle = 0;
        else if (sample_valid(cic->ttime_samples)) {
-               if (cic->ttime_mean > cfqd->cfq_slice_idle)
+               unsigned int slice_idle = cfqd->cfq_slice_idle;
+               if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
+                       slice_idle = msecs_to_jiffies(CFQ_MIN_TT);
+               if (cic->ttime_mean > slice_idle)
                        enable_idle = 0;
                else
                        enable_idle = 1;